Snazzy socks

I've been given a knitting problem (someone else's daughter's socks) and I don't understand the first part of the pattern.

Its Snazzy Socks from some paperleaf knitting pattern thing. I pmed the one person on Ravelry who had knit it, and she confessed that she hadn't understood it and had just done ribbing. Unfortunately, someone else has already knit the first sock, so I have to follow the pattern.

Can anyone help?

Socks: With pair of 5mm (no 6) needles and B, cast on 42 [52:62] sts. Working edging in rows as foll:

1st row: (RS) K1, yfwd, *k5, sl successively 2nd, 3rd, 4th and 5th sts just worked over 1st and off needle, yfwd, rep from *to last st, k1. 19[23:27]

Yfwd - from what I remember is just bringing the yarn to the front as if you were getting ready to purl. Meaning you'd end up with a yarn over. Right?

sl successively 2nd, 3rd, 4th and 5th sts just worked over 1st and off needle - this is the bit that reall doesn't make sense. Normally you slip the first st over the 2nd not the other way round (except for double decreases that want to centre on the middle st). Can anyone write this out for me in simple English? I don't mind if you sound patronising. I just can't see it.

Otherwise, I'm just going to give it back and claim defeat.